Self-locking turn buckle



July 2, 1957 D. E. CARPENTER SELF-LOCKING TURN BUCKLE Filed May 11, 1955 Q km m aw m INVENTOR n Darce/ E. Carpenter United States Patent SELF-LOCKING TURN BUCKLE Dar-eel E. Carpenter, Tulsa, Okla.

Application May 11, 1955, Serial No. 507,569

1 Claim. (Cl. 287'-60) This invention relates to turnbuckles.

It is an object of the present invention to provide a turnbuckle which is self locking and wherein the barrel portion will remain in a stationary position and retain a constant cable tension.

It is another object of the present invention to provide a self-locking turnbuckle which is simple to install, would represent an added safety factor in airplanes where con ventional turnbuckles are held together merely by safety wire and which could easily and readily be applied to equipment producing conventional turnbuckles by simply varying the length of the turnbuckle assembly.

It is still another object of the present invention to provide a selflocking turnbuckle which may be used without safety wires and all cables except control cables, efiecting thereby an economy of man hours normally required to attach the safety wire and wherein most of the load on the turnbuckle is due to tension with very little torque load.

It is still another object of the present invention to provide a self-locking turnbuckle which eliminates the need for safety wire to effect an economy of weight which is important in airplanes or the like.

For other objects and a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure 1 is a top plan view of a preferred embodiment of the present invention shown in operative assembly;

Fig. 2 is an exploded top plan view thereof showing the parts in disassembled relationship;

Fig. 3 is a longitudinal sectional view thereof taken along the line 3-3 of Fig. 1;

Fig. 4 is a transverse sectional view taken along the line 44 of Fig. 3; and

Fig. 5 is a transverse sectional view thereof taken along the line 55 of Fig. 3.

Referring now more in detail to the drawing, a barrel is provided and includes a central cylindrical portion integrally formed at opposite ends with the enlarged cylindrical portions 11 which terminate in the frusto-conical end portions 12, substantially as illustrated. The enlarged portions 11 are finished with an octagonal surface to facilitate tightening with a wrench or the like and are provided with the four equi-angularly spaced openings 13 which extend into the frusto-conical portions 12 and which permit the use of safety wire as an optional feature. However, due to its construction, the turnbuckle assembly of the present invention is self-locking and eliminates the need for such safety wire except in special cases, for example control cables.

As shown in Fig. 3, the cylindrical portion 10 is integrally formed with a transverse central wall 14 formed by a pair of internally threaded bores 15 and 16, the

internally threaded bores 15 and 16 continuing through the ends of the barrel in the enlarged internally threaded portions 17 and 13, respectively. The feature of the present invention resides in the fact that the inner internally threaded bores 15 and 16 are threaded oppositely t0 the other internally threaded bores 17 and 18 respectively. For example, the internally threaded bore 17 is provided with a right hand thread, while the internally threaded bore 15 is provided with a left hand thread. Similarly, the internally threaded bore 16 is provided with a right hand thread, while the internally threaded bore 18 is provided with a left hand thread.

A pair of terminals indicated generally at 19 are provided, each including a hollow cylindrical cable mounting portion 20 and an octagonal enlargement 21, substantially as illustrated. The cables 22 are secured within the cylindrical portions 20 in the usual manner while the octagonal enlargements 21 are provided with the equiangularly spaced grooves 23 which cooperate with the bores 13 of the barrel to receive therethrough the safety wire where necessary, in a manner well known to those skilled in the art. Each of the octagonal enlargements 21 is integrally formed with an externally threaded shank 24 adapted to be screwed into the internally threaded bores 17 and 18, one of the externally threaded shanks 24 being provided with a right hand thread, while the other is provided with a left hand thread. Each of the shanks 24 is in turn integrally formed with a reduced extension 25 which terminates in an externally threaded portion 26 adapted to be screwed into the internally threaded bores 15 and 16, one of the externally threaded portions 26 having a right hand thread, while the other is provided with a left hand thread. Each of the extensions 25 and externally threaded portions 26 thereof is provided with a pair of slots 27, 28, the slots 27 and 28 intersecting each other at substantially right angles and extending completely through the shank 26 thereof, (Fig. 4).

By means of special wrenches, the turnbuckle is assembled as shown in Fig. 3. By means of the reversed inside threads 17, 15 and 16, 18, one set of threads will tend to tighten the barrel onto the terminals while the other thread is loosened, and vice versa. This causes the barrel to remain set in a stationary position and to retain a constant cable tension. By means of such a construction, the necessity for safety wire is thus eliminated. In tightening, the internal threads 15 and 16 will squeeze together as they move from one thread in the barrel to the next, requiring a special spring type of steel in fabrication, which will permit the threads to return to their original position. The bores 13 and the grooves 23 are adapted for the optional use of safety wire and will be substantially twice the size of the wire itself, permitting the wire to slip in easily and readily.

While various changes may be made in the detail construction, it shall be understood that such changes will be within the spirit and scope of the present invention, as defined by the appended claim.

What I claim as new and desire to protect by Letters Patent of the United States is:

A self-locking turnbuckle comprising barrel means said barrel means at opposite ends having a first pair of internally threaded bores, second reduced internally threaded bores at the inner end of each of said first internally threaded bores, the threads on said reduced internally threaded bores being reversed relative to the threads on said first internally threaded bores adjacent thereto, and a pair of terminals, each of said terminals including an externally threaded shank adapted to be screwed into said first internally threaded bores and an externally threaded reduced extension adapted to be screwed into said second reduced internally threaded bores, each of said terminals having a reduced smooth cylindrical portion intermediate said externally threaded portion and externally threaded extension thereof, said smooth cylindrical portions and externally threaded extensions being continuously slotted, whereby to impart resiliency to the same, said slots extending therethrough in pairs disposed at substantially right angles to each other, one of said first internally threaded bores of said barrel means having a left hand thread, While the other is provided With a right hand thread, said internally threaded reduced bores and said barrel means having threads disposed oppositely to said right and left hand threads adjacent thereto, said externally threaded shanks and reduced externally threaded extensions on said terminals being correspondingly threaded.

References Cited in the file of this patent UNITED STATES PATENTS Lewis Oct. 6, Gafienraid Dec. 16, Willison Feb. 9, Podell Dec. 12, Wright May 11, 

